Advent of code day 1 part1 rust

aoc-2023-day01-part1.rs

use tracing;
use std::fs;
use miette::Result;
use crate::aoc_error;

pub fn main() {
    let contents = fs::read_to_string("2023-day-01-part1")
        .expect("Should have been able to read the file");
    let result = calculate(contents); //55172
    match result {
        Ok(v) => println!("Result is: {v:?}"),
        Err(e) => println!("Error!: {e:?}")
    }
}

#[tracing::instrument]
fn calculate(input : String) -> Result<u32, aoc_error::AoCError> {

    let mut sum = 0;
    let lines = input.lines();
    for line in lines {
        let mut first = 10;
        let mut last = 10;
        let length = line.len();
        let chars: Vec<char> = line.chars().collect();
        for first_index in 0..chars.len() {

            if first == 10 {
                let first_char = chars[first_index];
                let first_digit = first_char.to_digit(10);
                match first_digit {
                    None => {}
                    Some(value) => {
                        first = value;
                    }
                }
            }
            if last == 10 {
                let last_index = (length - 1) - first_index;
                let last_char = chars[last_index];
                let last_digit = last_char.to_digit(10);
                match last_digit {
                    None => {}
                    Some(value) => {
                        last = value;
                    }
                }
            }
        }
        let number = first * 10 + last;
        sum += number;
        //dbg!(number);
    }

    return Result::<u32, aoc_error::AoCError>::Ok(sum);
}

#[test]
fn it_works() -> Result<()> {
    let input = "1abc2 //12
pqr3stu8vwx //38
a1b2c3d4e5f //15
treb7uchet"; // 77
    assert_eq!(142, calculate(input.to_string())?);
    Ok(())
}